﻿using System;
using System.Web;
using System.Web.SessionState;
using System.Security.Principal;

using System.Web.Security;
using UCENTRIK.Membership;

using System.IO;
using System.Text.RegularExpressions;




namespace UCENTRIK.HttpModules
{


    /// <summary>
    /// Removes whitespace from the webpage.
    /// </summary>
    public class UcWhitespaceModule : IHttpModule
    {



        #region IHttpModule Users

        void IHttpModule.Dispose()
        {
            // Nothing to dispose; 
        }

        void IHttpModule.Init(HttpApplication context)
        {
            context.BeginRequest += new EventHandler(context_BeginRequest);
        }

        #endregion






        void context_BeginRequest(object sender, EventArgs e)
        {
            HttpApplication app = sender as HttpApplication;
            if (app.Request.RawUrl.Contains(".aspx"))
            {
                app.Response.Filter = new WhitespaceFilter(app.Response.Filter);
            }
        }








        #region Stream filter

        private class WhitespaceFilter : Stream
        {

            public WhitespaceFilter(Stream sink)
            {
                _sink = sink;
            }

            private Stream _sink;
            private static Regex reg = new Regex(@"(?<=[^])\t{2,}|(?<=[>])\s{2,}(?=[<])|(?<=[>])\s{2,11}(?=[<])|(?=[\n])\s{2,}");




            #region Properites
            //--------------------------------------------------------------------------------
            public override bool CanRead
            {
                get { return true; }
            }

            public override bool CanSeek
            {
                get { return true; }
            }

            public override bool CanWrite
            {
                get { return true; }
            }

            public override void Flush()
            {
                _sink.Flush();
            }

            public override long Length
            {
                get { return 0; }
            }

            private long _position;
            public override long Position
            {
                get { return _position; }
                set { _position = value; }
            }
            //--------------------------------------------------------------------------------
            #endregion





            #region Methods
            //--------------------------------------------------------------------------------
            public override int Read(byte[] buffer, int offset, int count)
            {
                return _sink.Read(buffer, offset, count);
            }

            public override long Seek(long offset, SeekOrigin origin)
            {
                return _sink.Seek(offset, origin);
            }

            public override void SetLength(long value)
            {
                _sink.SetLength(value);
            }

            public override void Close()
            {
                _sink.Close();
            }

            public override void Write(byte[] buffer, int offset, int count)
            {
                byte[] data = new byte[count];
                Buffer.BlockCopy(buffer, offset, data, 0, count);
                string html = System.Text.Encoding.Default.GetString(buffer);

                html = reg.Replace(html, string.Empty);

                byte[] outdata = System.Text.Encoding.Default.GetBytes(html);
                _sink.Write(outdata, 0, outdata.GetLength(0));
            }
            //--------------------------------------------------------------------------------
            #endregion




        }

        #endregion

    }



}
